The elements and operation of a toilet are well known in the art. In FIGS. 1 and 2, two of the most common toilets are shown, a ballcock toilet 100 (FIG. 1) and a floating cup toilet 200 (FIG. 2). In the Figs. and the disclosure that follows, like parts receive like numerals, although differing by 100. In each embodiment, a bowl 102, 202 receives human waste, and a water tank 104, 204, defined by walls 105, 205 holds flush water W capable of initiating a syphon action when released from the water tank 104, 204 into the bowl 102, 202. Although variations exist, these types of toilets 100, 200 are generally flushed by manipulating a flush mechanism 106, 206 that includes a flush handle 108, 208 connected to a lever arm 110, 210 that is connected to a flush valve 112, 212 through a linkage 114 or chain 214. The flush valve 112, 212 seals a drain hole 116, 216 within the water tank 104, 204, and pushing the flush handle 108, 208 causes the flush valve 112, 212 to unseat from the drain hole 110, 210 such that the flush water W enters the toilet bowl 102, 202 from the water tank 104, 204, initiating a syphon so that all of the water and waste in the toilet bowl is flushed.
As the water in the tank 104, 204 drains, a filler float 118, 218 falls with the water level and turns on a filler valve 120, 220 through the operative connection between filler float 118, 218 and filler valve 120, 220. In the embodiment of FIG. 1, the connection is a float lever arm 122 that connects between filler valve 120 and ballcock filler float 118. In the embodiment of FIG. 2, the connection is a push rod 222 that connects between filler valve 220 and sleeve filler float 218. When water tank 104, 204 is filled with flush water W, as shown in FIGS. 1 and 2, filler float 118, 218 occupies a shut-off position, wherein filler valve 120, 220 is closed to the passage of refill water. But filler float 118, 218 rises and falls with the level of flush water W in water tank 104, 204 such that, when flushing mechanism 106, 206 is manipulated to flush bowl 102, 202, the level of flush water W within water tank 104, 204 begins to fall, and filler float 118, 218 falls with it. Once filler float 118, 218 has fallen a short distance with flush water W, it may be considered to occupy a refill position, wherein filler valve 120, 220 allows for the passage of refill water therethrough to refill both bowl 102, 202 and water tank 104, 204. When filler float 118, 218 occupies the refill position, filler valve 120, 220 sends refill water in two directions—into water tank 104, 204 and through overflow tube 124, 224 into bowl 102, 202. It will be appreciated that the refill water filling water tank 104, 204 causes filler float 118, 218 to rise, eventually occupying the shut-off position and closing filler valve 120, 220 to the passage of refill water, ending the refill cycle.
Should a clog in the siphon or bowl occur, water entering bowl 102, 202 will flood the bowl and eventually spill over onto the floor. If the flush valve 112, 212 does not seat properly on drain hole 116, 216 during the tank refill cycle, water entering the tank 104, 204 through filler valve 120, 220 will flow to bowl 102, 202 and will not fill tank 104, 204. Consequently, the filler float 118, 218 will not rise, the filler valve 120, 220 will not be closed, and water will continue to flow to bowl 102, 202 and the floor. Thus, control mechanisms have been proposed for selectively closing the filler valve 120, 220. Although control mechanisms have been addressed in the prior art, as, for example, in U.S. Pat. Nos. 4,402,093, 4,633,534, 5,083,323, and 6,016,577 the present invention provides a very straight forward and user friendly mechanism and method for preventing toilet overflow.